Simplify LwtRandom

src/web/web_common.ml

@@ -27,26 +27,18 @@ open Web_serializable_j
 
 let spool_dir = ref "."
 
-let make_rng = Lwt_preemptive.detach (fun () ->
-  pseudo_rng (random_string secure_rng 16)
-)
-
-module type LWT_RANDOM = Signatures.RANDOM with type 'a t = 'a Lwt.t
-
-module type LWT_RNG = sig
-  val rng : rng Lwt.t
-end
-
-module MakeLwtRandom (X : LWT_RNG) = struct
+module LwtRandom = struct
 
   type 'a t = 'a Lwt.t
   let return = Lwt.return
   let bind = Lwt.bind
   let fail = Lwt.fail
 
+  let prng = lazy (pseudo_rng (random_string secure_rng 16))
+
   let random q =
     let size = Z.bit_length q / 8 + 1 in
-    let%lwt rng = X.rng in
+    let%lwt rng = Lwt_preemptive.detach Lazy.force prng in
     let r = random_string rng size in
     return Z.(of_bits r mod q)
 

src/web/web_common.mli

@@ -19,21 +19,12 @@
 (*  <http://www.gnu.org/licenses/>.                                       *)
 (**************************************************************************)
 
+open Signatures
 open Web_serializable_t
 
 val spool_dir : string ref
 
-val make_rng : unit -> Platform.rng Lwt.t
-(** Create a pseudo random number generator initialized by a 128-bit
-    secure random seed. *)
-
-module type LWT_RANDOM = Signatures.RANDOM with type 'a t = 'a Lwt.t
-
-module type LWT_RNG = sig
-  val rng : Platform.rng Lwt.t
-end
-
-module MakeLwtRandom (X : LWT_RNG) : LWT_RANDOM
+module LwtRandom : RANDOM with type 'a t = 'a Lwt.t
 (** Lwt-compatible random number generation. *)
 
 type error =

src/web/web_site.ml

@@ -39,8 +39,6 @@ module PString = String
 open Eliom_service
 open Eliom_registration
 
-module LwtRandom = MakeLwtRandom (struct let rng = make_rng () end)
-
 (* Table with elections in setup mode. *)
 let election_stable = Ocsipersist.open_table "site_setup"